Effects of Straw Mulching on Soil Temperature and Maize Growth in Northeast China

In China, corn is growing in large quantities, and a large amount of straw is produced each year. Improper straw treatment may cause environmental problems. Covering the fields after straw crushing can prevent soil erosion and increase soil fertility, which has become a recommended method of straw treatment. The effects of straw mulching on soil water content, soil temperature and maize growth traits were analyzed through comparative experiments. The results showed that straw mulching had heat insulation effect. In May and June, when the average temperature was low, straw mulching kept the ground temperature at a low value, resulting in late emergence of crops and poor growth in the nutritional stage. In July and August when the temperature is higher, the higher ground temperature is maintained, which makes the crop grow better in reproductive growth stage and yield higher. In addition, straw mulching makes the soil water content higher and has a positive effect on Maize Cultivation in northeastern China for Rain-fed agriculture

The Classification of Rice Blast Resistant Seed Based on Ranman Spectroscopy and SVM

Rice blast is a serious threat to rice yield. Breeding disease-resistant varieties is one of the most economical and effective ways to prevent damage from rice blast. The traditional identification of resistant rice seeds has some shortcoming, such as long possession time, high cost and complex operation. The purpose of this study was to develop an optimal prediction model for determining resistant rice seeds using Ranman spectroscopy. First, the support vector machine (SVM), BP neural network (BP) and probabilistic neural network (PNN) models were initially established on the original spectral data. Second, due to the recognition accuracy of the Raw-SVM model, the running time was fast. The support vector machine model was selected for optimization, and four improved support vector machine models (ABC-SVM (artificial bee colony algorithm, ABC), IABC-SVM (improving the artificial bee colony algorithm, IABC), GSA-SVM (gravity search algorithm, GSA) and GWO-SVM (gray wolf algorithm, GWO)) were used to identify resistant rice seeds. The difference in modeling accuracy and running time between the improved support vector machine model established in feature wavelengths and full wavelengths (200–3202 cm−1) was compared. Finally, five spectral preproccessing algorithms, Savitzky–Golay 1-Der (SGD), Savitzky–Golay Smoothing (SGS), baseline (Base), multivariate scatter correction (MSC) and standard normal variable (SNV), were used to preprocess the original spectra. The random forest algorithm (RF) was used to extract the characteristic wavelengths. After different spectral preproccessing algorithms and the RF feature extraction, the improved support vector machine models were established. The results show that the recognition accuracy of the optimal IABC-SVM model based on the original data was 71%. Among the five spectral preproccessing algorithms, the SNV algorithm’s accuracy was the best. The accuracy of the test set in the IABC-SVM model was 100%, and the running time was 13 s. After SNV algorithms and the RF feature extraction, the classification accuracy of the IABC-SVM model did not decrease, and the running time was shortened to 9 s. This demonstrates the feasibility and effectiveness of IABC in SVM parameter optimization, with higher prediction accuracy and better stability. Therefore, the improved support vector machine model based on Ranman spectroscopy can be applied to the fast and non-destructive identification of resistant rice seeds

Forming and Degradation Mechanism of Bowl Seedling Tray Based on Straw Lignin Conversion

In response to the problems of low straw utilization efficiency and poor returning effect in Northeast China, this paper takes rice straw containing cow dung as the experimental material, and according to the characteristics of lignin glass transformation of the material, proposes a new method to prepare biomass seedling trays. The seedling trays prepared by this method can meet the needs of corn seedling cultivation and transplantation. To study the molding mechanism, scanning electron microscopy and a universal testing machine were used to compare the changes in the internal structure and mechanical properties of the regularly- and hot-compressed seedling trays before and after seedling raising. The results show that the material with water content of 23% has the best hot-pressing effect. The forming mechanism is: that the strength of the molded seedling tray resulted from the mechanical setting force of the multilayered stem fibers with a mosaic structure within the seedling tray. The adhesion and wrapping by lignin prevented water penetration from damaging the multilayered stem fibers and slightly improved their strength. The seedling tray made of straw and manure was completely degraded over 40 days, and the straw degradation rate was improved. This method can increase the overall quality and benefits of straw, providing a foundational reference for high-quality and high-efficiency straw utilization

The complete mitochondrial genome sequence and phylogenetic position of Sinocyclocheilus xiaotunensis (Cypriniformes: Cyprinidae)

The complete mitochondrial DNA genome of Sinocyclocheilus xiaotunensis was first reported by next-generation sequencing method. The entire length of mitochondrial genome is 16,588 bp and the nucleotide composition was made up of 32.3% A, 25.0% T, 27.2% C, and 15.5% G, indicating an A + T(57.3%) content is greater than C + G(42.7%). The mitogenome is a circular DNA molecule with a D-loop region and contains 22 transfer RNA (tRNA) genes, two ribosomal RNA(rRNA) genes and 13 protein-coding genes.To provide further info on the conserved sequence block observed in the control region of the mitochondrial genome. This info is critical for future application and determination of taxonomic status of this species

Detection of Large Herbivores in UAV Images: A New Method for Small Target Recognition in Large-Scale Images

Algorithm design and implementation for the detection of large herbivores from low-altitude (200 m–350 m) UAV remote sensing images faces two key problems: (1) the size of a single image from the UAV is too large, and the mainstream algorithm cannot adapt to it, and (2) the number of animals in the image is very small and densely distributed, which makes the model prone to missed detection. This paper proposes the following solutions: For the problem of animal size, we optimized the Faster-RCNN algorithm in terms of three aspects: selecting a HRNet feature extraction network that is more suitable for small target detection, using K-means clustering to obtain the anchor frame size that matches the experimental object, and using NMS to eliminate detection frames that have sizes inconsistent with the size range of the detection target after the algorithm generates the target detection frames. For image size, bisection segmentation was used when training the model, and when using the model to detect the whole image, we propose the use of a new overlapping segmentation detection method. The experimental results obtained for detecting yaks, Tibetan sheep (Tibetana folia), and the Tibetan wild ass in remote sensing images of low-altitude UAV from Maduo County, the source region of the Yellow River, show that the mean average precision (mAP) and average recall (AR) of the optimized Faster-RCNN algorithm are 97.2% and 98.2%, respectively, which are 9.5% and 12.1% higher than the values obtained by the original Faster-RCNN. In addition, the results obtained from applying the new overlap segmentation method to the whole UAV image detection process also show that the new overlap segmentation method can effectively solve the problems of the detection frames not fitting the target, missing detection, and creating false alarms due to bisection segmentation

Evaluation of High Efficiency and Low Fish Meal Diets for Golden Pompano (Trachinotus ovatus) in Deep-Sea Cage Culture

Trachinotus ovatus, commonly known as golden pompano, is a euryhaline warm water carnivorous fish. It has the characteristics of fast growth, simple feeding, delicious meat, strong stress resistance, and high survival rate. It can accept compound feed throughout its growth. It is popular among fish breeders and consumers because of its moderate specifications and affordable price. With an annual output of 240 000 tons, it has become one of the most important marine fish breeding species in the southern coastal areas of China. As a marine carnivorous fish, it has specific requirements relating to the levels and sources of dietary protein and fat, and a strong dependence on fish meal and fish oil, which are limited resources with high prices, which also determines its high feed cost. However, compared with other rare sea fish, its price is low and the profit margin of breeding is low (2–4 CNY/kg), thus, easily leading to the loss of breeding enterprises and individual businesses. Therefore, it is necessary to develop efficient and low-cost compound diets and reduce the supplemental level of fish meal oil in diets to solve the bottleneck problem of golden pompano fish breeding. Previous studies have shown that T. ovatus subjected to a high efficiency and low fish meal diet exhibited excellent growth and health in pond cage culture. To further evaluate the application effect of this feed in deep-sea cage culture, an experimental feed (crude protein 47.66%, crude fat 7.98%) based on the formula feed of a low fish meal diet was produced by a feed company with a large-scale production process (feed production using large machinery and mass production in a feed mill with an hourly output that can reach more than 10 t using equipment such as oil sprayer machines, where the fat source is added by spraying). A commercial feed from a well-known brand was used as the control diet (crude protein 47.75%, crude fat 9.63%). Large-sized golden pompano (mean body weight ~262 g) were provided by Yangjiang Haina Fisheries Limited and kept for 2 weeks at the deep-sea cage breeding base in Dasuo Island, Yangjiang (12–20 m depth, about 15 km offshore) to adapt to the test environment. During the temporary feeding period, a well-known commodity was used for feed. Overall, 150 000 healthy large-sized golden pompano with neat specifications (initial body weight ~260 g) were selected and randomly assigned to six deep-sea cages (HDPE C60 floating cages, circumference 60 m, 25 000 fish per cage). Each feed was provided in three parallel cages for 33 days (April 29 to May 31, 2021). During breeding, full food was provided twice a day (07:00 and 17:00). During the experiment, the seawater temperature was 20.00~29.00 ℃. Dissolved oxygen was 6.30~7.80 mg/L. The results showed that the growth performance of fish was not statistically different between the two groups (P > 0.05). However, compared with the control group, the weight gain rate and specific growth rate of fish-fed experimental diets increased by 14.43 % and 8.19 %, respectively, and the average daily weight gain increased by 0.68 g. In terms of muscle nutrition and texture characteristics, the muscle lipid contents of the fish-fed experimental diets were significantly higher than those of fish-fed control diets (P 0.05). Compared with the control group, the serum protein, triglyceride, total cholesterol, and low-density lipoprotein contents, as well as the activity of aspartate aminotransferase, of fish fed the experimental diet were significantly decreased (P 0.05). In addition, the feed cost per 1 kg of fish receiving the experimental diet was 18.80% lower than that of fish receiving the control diets, and its culture benefit was increased by 62.12%. The results showed that the experimental diet (high efficiency and low fish meal diet) not only promoted growth, but also improved the muscle fat level and serum lipid metabolism of the fish. These results indicate that the high efficiency and low fish meal diet can be applied in the culture of golden pompano within deep-sea cages. In this study, a high efficiency and low fish meal diet for T. ovatus was developed by using amino acid balance technology and fatty acid precision nutrition technology in deep-sea cage large-scale culture. Through the analysis of growth performance, serum biochemical parameters, liver lipid metabolism, and antioxidant properties, it was found that the growth promoting effect of test material was comparable to that of commercial material, and could improve the muscle quality and liver health of golden pompano. Use of the experimental diet could also reduce the cost of breeding, improve the economic benefits, and result in high economic value. The results indicate that the experimental high efficiency and low fish meal diet for T. ovatus has a good application effect and excellent market development prospects, and also has important practical guiding significance for the large-scale production and application of high efficiency low fish meal compound feed, solving the problem of aquaculture bottleneck and facilitating deep-sea golden pompano culture

Effects of Dietary Animal Protein Source Composition on the Growth Performance, Intestinal Health, and Protein Metabolism of Largemouth Bass (Micropterus salmoides)

Terrestrial animal protein sources contain less antinutritional factors, high protein content, and functional factors, which are beneficial to fish health. Among them, poultry byproduct meal (containing 65%-73% protein rich in vitamins) and porcine meat meal (containing 45%-60% protein and high contents of proline and glycine) are the most widely used meals in aquatic compound feeds, and are important fish meal replacement sources. As a carnivorous fish species, largemouth bass (Micropterus salmoides) is highly dependent on dietary fish meal, and the level of fish meal added in its commercial feeds is up to 50%. However, the rising price of fish meal increases the farming cost of M. salmoides. Therefore, it is necessary to identify a suitable alternative protein source to reduce the amount of dietary fish meal and the feed cost. Therefore, seven compound feeds (D1-D7) were prepared in this study. The added ratios of fish meal/poultry byproduct meal/porcine meat meal were as follows: 45.0/22.6/0, 37.1/22.6/8.0, 28.8/22.6/16.0, 45.0/14.5/8.0, 45.0/5.3/16.0, 41.6/18.0/8.0, and 37.0/13.8/16.0. Juvenile M. salmoides (initial body weight ~55 g) were fed the above diets for 60 days with five replicates in each group. The effects of the animal protein source combination on the growth performance, tissue biochemical indices, muscle texture characteristics, liver protein metabolism, and intestinal inflammatory factor-related gene expression were evaluated. The water temperature during the feeding trial was 27.4-32.3 ℃ and the ammonia nitrogen concentration was 0.1-0.2 mg/L. After the feeding experiment, three fish were randomly selected from each cage to collect the serum, liver, intestinal tract, muscle, and other samples, which were then stored at -80 ℃. In addition, three fish were randomly selected from each cage to determine their morphological indices. At the same time, two fish were selected from each cage to determine the muscle texture characteristics and the whole fish proximate composition. Physiological and biochemical indices of serum and liver tissues, albumin, urea nitrogen (BUN), total amino acid (T-AA), alanine aminotransferase (ALT), aspartate aminotransferase, total protein (TP), and blood ammonia (SA) levels), were determined using commercial kits, and the texture characteristics of muscle were determined by using a texture analyzer. The moisture, crude fat, crude protein, and ash contents of whole fish and muscle were determined by atmospheric drying, Soxhlet extraction, Kjeldahl nitrogen determination, and Muffle furnace incineration, respectively. Real-time quantitative PCR was used to determine the expression levels of genes related to liver protein metabolism and the intestinal inflammatory response. All test data were expressed as the mean±standard error, and multiple comparisons were made by the Tukey test, with P 0.05). The whole-body crude protein content in the D3 group was significantly higher than that in the D1 group, and the crude lipid level in the D3 group was significantly lower than that in the D6 group (P 0.05). The serum T-AA content of fish in the D3 group was significantly higher than that in the D1 and D4 groups (P 0.05). In terms of muscle quality, the muscle hardness, adhesion, and mastication in the D3 group were significantly lower than those in the D4 and D6 groups, respectively (P 0.05). In addition, the mRNA expression levels of intestinal il-10 and liver tor, s6k1, akt, and pi3k in the D3 group were upregulated, and were significantly higher than those in the D7 group (P < 0.05). The mRNA expression levels of il-1β and il-6 in the intestines and 4ebp-1 in the liver of the D3 group were significantly lower than those of the D1 group (P < 0.05). These results indicated that combined use of 28.8% fish meal, 16.0% porcine meat meal, and 22.6% poultry byproduct meal had the best growth promotion effect on M. salmoides, and was able to improve liver protein synthesis and maintain intestinal health. The results of this study provided technical support for reducing the dependence of M. salmoides compound feed on fish meal